2019
January 07, 2019
Sponsored by:
A Thermographer’s Magic Marker
Tip suggested by: Randall D. Cain, American Water Company
An age-old challenge for thermographers is the ability to annotate or mark objects to make them easier to identify in recorded imagery. One possible solution is to mark targets with an ink pen with low emittance ink.
Many thermographers have long sought ways to mark targets in such a fashion that numbers or text can clearly be seen with a thermal imager. Over time, some thermographers have used paints with emittances that contrast sharply with the objects being marked. In these cases, text and/or numbers painted on the target are clearly visible within resulting thermal imagery and recorded thermograms.
Recently some thermographers have reported good results in utilizing a Sharpie permanent felt-tip marker in silver color. The low emittance of the metallic ink contrasts markedly with high emittance targets allowing annotations to clearly appear within thermal images. In many cases, the silver ink can also be clearly seen in daylight images as well. An example can be seen below.
One should be aware that Sharpie markers are permanent unless the ink is applied to a removable material such as tape or labels affixed to the target. Prior to marking any target, be certain it is safe to do so and that marking will not permanently damage the target.
For more information on thermographer training and certification or to obtain a copy of the Standard for Infrared Inspection of Electrical Systems and Rotating Equipment, call Infraspection Institute at 609-239-4788 or visit us online at wwww.infraspection.com.
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January 14, 2019
Sponsored by:
Cold Weather Clothing
Tip written by: Infraspection Institute
Cold weather clothing is a matter of functionality not fashion. Clothing needs to be worn in layers in order to trap air which is warmed by the body. When selecting clothing, start with the innermost layer and work outward. The use of multiple layers will trap warm air while providing greater ease of movement. As you add layers, be sure to adjust the next layer’s size accordingly.
The first layer should be made of a synthetic material that will wick perspiration away from the body and maintain its insulating properties when damp. The second layer is your main insulator and should be a breathable material that maintains its insulating properties when wet. Synthetic fleeces or natural wool are good choices. The outermost layer should be breathable and both wind and water resistant.
Head and neck protection is a must since nearly 40% of body heat is lost here. Perspiration is the main enemy of feet. The best footwear will have sturdy outers, good treads and a removable felt liner. Buy extra liners and replace them every few hours. Liners can take a full day to fully dry out so buy enough to get through a typical workday.
Mittens are the warmest but present problems in grasping tools, etc. I have found that a heavy duty welder’s glove with cotton or wool gloves lining them provide good warmth and mobility. Buy enough liners to get you through the day. One final note, the body needs fuel to produce heat. Your calorie needs increase in cold weather and require regular replenishment with good wholesome foods.
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January 21, 2019
Sponsored by:
IR Inspections of Electric Motors
Tip written by: Infraspection Institute
Despite the important role they play in a commercial facility, electric motors tend to be both out-of-sight and out-of-mind until they fail. Infrared thermography can be used as a cost-effective diagnostic tool for detecting problems within electric motor systems.
Many infrared inspection programs include motor control circuits but overlook the motor itself. Evidence of several conditions which can lead to premature motor failure can be detected with a thermal imager. The following are suggestions for thermographically inspecting motors.
- With cover removed, inspect electrical connections at the motor junction box. This should be done in conjunction with the regularly scheduled inspection of the facility’s electrical system.
- Inspect motor casing for localized hotspots which may be indicative of short circuits within motor windings
- Qualitatively compare individual motors to similar motors under similar load
- When possible, qualitatively compare inboard and outboard bearings for each motor. If a large Delta T is present, it may be indicative of misalignment or a rotor balance problem. If both bearings are hot, the bearings may be worn or improperly lubricated.
Because no complicated analysis is required, infrared inspections typically can be performed rapidly and at a fraction of the cost of other types of motor testing. Additionally, infrared can detect evidence of misalignment at lower thresholds than those detectable by vibration analysis and motor current signature analysis.
Lastly, infrared inspections of motor bearings and stator should be performed monthly by experienced, certified infrared thermographers who thoroughly understand the theory and operation of electric motors.
Infrared inspection of electric motors is one of the many topics covered in the Level I Infraspection Institute Certified Infrared Thermographer® training course. For information on thermographer training including our Distance Learning courses, visit us online at www.infraspection.com or call us at 609-239-4788.
January 28, 2019
Sponsored by:
IR Inspections of Electrical Bus Ducts
Electrical bus ducts are a common feature found in many commercial and industrial electrical systems. When used to supplement regular PM, infrared inspections can help to detect loose or deteriorated connections that can lead to costly catastrophic failures.
Electrical bus ducts are used to distribute low voltage power throughout many industrial facilities. Modern bus ducts are unitized structures that contain insulated conductors within a steel casing. Individual sections of bus duct, each typically 10 feet long, are joined with bolted connections at the end of each bus section. Published industry standards recommend that bus duct connections be manually tightened every six months.
Even with regular tightening of bus duct connections, loose/deteriorated connections are difficult to detect. With the bus duct under load, a thermal imager can readily detect the temperature differentials associated with loose connections. Properly functioning bus ducts should exhibit no temperature differential in the vicinity of bolted connections. Because bus duct conductors are hidden from direct line of sight, any inexplicable temperature differentials should be investigated and corrected immediately. Disconnect switches and cable connections should be checked for thermal anomalies as well.
To ensure complete coverage, bus duct should be inspected from both sides of the duct along its entire length. Termination cabinets should also be inspected once the covers have been removed. Annual or semi annual infrared inspections performed by certified, experienced thermographers should be used to supplement regular bus duct maintenance.
Infrared inspection of bus ducts and electrical distribution systems are two of the many topics covered in the Level I Infraspection Institute Certified Infrared Thermographer® training course. For information on thermographer training or to obtain a copy of the Standard for Infrared Inspection of Electrical Systems & Rotating Equipment, visit us online at www.infraspection.com or call us at 609-239-4788.
February 04, 2019
Sponsored by:
Is Distance Learning Right For You?
Tip written by: Infraspection Institute
Advancements in technology have reshaped traditional approaches to education. Students are now able to study a wide variety of subjects, including thermography, from virtually anywhere in the world.
Distance learning may be defined as any situation where the student and the instructor are in physically separate locations. Distance instruction may be live or pre-recorded and can be delivered via video presentations, remote teleconferencing, and web-based presentations.
Distance learning provides several advantages over the traditional classroom setting. Chief among these are the elimination of travel costs, 24 hour availability, and increased convenience in scheduling. The availability of Distance Learning courses for thermography is particularly beneficial to thermographers with hectic schedules.
When selecting Distance Learning courses for thermography, be sure to determine the following:
- How and when is course delivered
- Length of course and curriculum
- What standards does course curriculum conform to
- Are experienced instructors available to answer questions
- Does course qualify toward thermographer certification
- Experience of training firm in providing thermographic instruction
Infraspection Institute offers a wide variety of Distance Learning courses for thermography. Courses include: Certification Prep, Applications and Industry-Specific Courses. All courses are ASNT compliant and are taught by Level III Infraspection Institute Certified Infrared Thermographers® each having over 20 years experience. For more information on Infraspection’s Distance Learning Courses, call us at 609-239-4788 or visit the Infraspection website.
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February 11, 2019
Sponsored by:
Preventing Falls in Icy Weather
Tip provided by Conoco Phillips
Numerous injuries result from slips and falls on icy sidewalks, parking lots, roads and other outdoor locations every year. Snow removal, sanding and salting of these types of areas can help but, many times, total elimination of snow/ice hazards are impossible and other measures must be used to cope with these problems.
Focus on your walking path and pick steps that minimize or eliminate your exposure to icy slips. This is a time during which keeping your “eyes and mind on path” is more critical than ever.
Accept and anticipate the fact that you are at risk of falling at any given moment when walking on ice. Adjust your stride so your center of gravity is maintained as directly above your feet as possible by taking shorter steps than usual.
Don’t ignore the hazard presented by a slippery surface in your immediate path or work area. Take the time to spread sand, salt, or calcium chloride on icy areas and notify your Supervisor if further action is necessary. Keep in mind that salt (chloride) containing material is incompatible with stainless steel and is not to be used where contact can be made.
Footwear should have slip resistant soles. Avoid leather soled shoes. Equate this to driving a car with bald tires in the winter. You need something suitable to grip the surface you intend to walk on.
Wipe your feet off at the entrance of buildings so others won’t slip and fall on melted snow that has been tracked into the building.
Like the ice under your feet, beware of icicles over your head; they can be dangerous. Although you cannot stop them from forming, you can minimize their effects by controllably knocking them down.
Whether you’re dealing with an overhead or underfoot ice hazard, if you can’t control it, barricade or rope the area off.
When walking down stairs with or without an item in one hand, Safety In Motion has a technique that can reduce your chance of falling down the stairs. Grasp the handrail in the palm up position trailing behind you instead of your direction of travel. Your feet should be positioned at a slight angle toward that railing. Should you loose your balance, your grip on the handrail in this position will cause you to come to a stop against the handrail instead of falling down the stairs. Try the technique and become comfortable with it before you need it. Make protecting yourself a top priority!
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February 18, 2019
Sponsored by:
IR Inspections of Furnace Tubes
Tip written by: Infraspection Institute
Process furnaces or heaters are a critical component found in many petrochemical refineries. Performed properly, infrared inspections of furnace tubes can provide valuable data regarding tube condition and operating temperature.
Process heaters are large, refractory-lined structures used to heat hydrocarbon product during refining. Process heaters are similar to steam boilers in their construction except that hydrocarbon is passed through the firebox tubes instead of water. Safe operation of process heaters requires that tubes operate below their maximum operating temperature. Overheating of tubes can reduce operational life or lead to catastrophic failure.
Measuring tube temperatures is difficult for many reasons. Tubes are often remotely located from inspection ports and are frequently obscured by visually opaque flames. High temperature environments make contact measurements difficult or impossible. Under the right circumstances, infrared thermography can be used to provide qualitative and quantitative data for in-service heater tubes. The following images were taken through viewports on operating heaters.
Image taken through opaque flame.
Image taken through opaque flame.
Infrared inspection of process furnaces or heaters is one of the most difficult tasks for thermal imaging and infrared radiometry. Accuracy in temperature measurement is of paramount importance since many companies utilize infrared data to determine safe operating limits for in-service heaters.
Far from being a “point and shoot” application, a thermographer needs to understand heater operation and heat transfer as well as issues pertinent to thermography. These include, but are not limited to: infrared camera selection including proper spectral response and spot measurement size; imager calibration; use of filters, windows and heat shields; calculating emittance and reflected temperature; equipment precision and accuracy; and how to obtain reliable reference temperatures to verify proper imager settings.
To help ensure accuracy, thermographers should be trained to at least Level II and, when possible, work with an experienced mentor until they have gained sufficient field experience.
Infrared inspection of process heater tubes is one of the applications covered in the Infraspection Institute Level II Certified Infrared Thermographer® training courses. For more information or course schedules, visit us online at www.infraspection.com or call us at 609-239-4788.
More information on this subject is available via a free download from our website at: Applications of Infrared Thermography for Petrochemical Process Heaters.
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February 25, 2019
Sponsored by: Testo Inc.
First Impressions Count
Tip written by: Infraspection Institute
“First impressions count.” This timeless observation underscores the importance of appearances when meeting someone for the first time. This same observation also holds true in the modern, wired world.
Experienced businesspeople know the importance of first impressions. To this end, they do their best to dress, act, and speak appropriately when meeting prospects. Why is it then that so many fail to understand that first impressions on the web are equally important?
The worldwide web and email have greatly expanded the reach of many businesses. No longer are businesses confined to geographic regions; their ability to reach a worldwide audience is limited only by the connectivity of their prospects.
Prospects will form opinions about businesses or individuals through their websites, emails and posts to social media. When using any of these resources, keep the following in mind:
- Be courteous and respectful of others.
- Never post anything you should not say in public.
- Do not make personal attacks on individuals or companies.
- The internet crosses international and cultural boundaries. Depending on local customs, people do things differently. This does not make them wrong.
Remember, with every new encounter, others form impressions of you. Because first impressions can be permanent, make certain that your web impressions are always positive.
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Calculating Field of View
Have you ever wondered what the size of your imager’s field of view is at a given distance? If you know the visual field of view specifications for a thermal imager, it is possible to calculate the size of your imager’s viewing area for any given distance using a scientific calculator. The formula for this calculation is:
{(tangent 1/2 viewing angle) x distance} x 2
To apply the above formula, follow these steps:
1. Determine your imager’s Field of View (in degrees) from the manufacturer’s specs.
2. Divide the value from Step 1 by 2
3. Use scientific calculator to determine tangent of number obtained in Step 2
4. Multiply number in Step 3 by distance from imager lens to object.
5. Multiply number obtained in Step 4 by 2. This will be the width of the imager’s field of view at the specified distance.
Example: Calculate field of view for 16° lens at 25’.
(tan 8° x 25’) x 2 =
(0.140541 x 25’) x 2 =
(3.513525’) x 2 = ˜ 7.0’
If your imager specifies different Field of View values for horizontal and vertical, it will be necessary to calculate each value separately. Calculated values should be used for estimation purposes as actual values may vary slightly.
Imager operation is one of the many topics covered in all Infraspection Level I and Level II training courses. For more information on our Distance Learning Program or our open enrollment classes, visit us online at Infraspection.com or call us at 609-239-4788.
Begin With the End in Mind
“Begin with the end in mind” is a frequent quotation from Stephen Covey’s best selling book, The 7 Habits of Highly Effective People. Applying this principle can have a dramatic impact on many things including an infrared inspection program.
Prior to undertaking any task or project, it is important to have a clear understanding of what the final outcome should be. With this vision in mind, one is able to gauge the effectiveness of their efforts in achieving goals. By beginning with the end in mind, one knows what the goals are and can help chart a course of action that leads directly to these goals.
Building an infrared inspection program is like a construction project. You need to have a clear understanding of what you desire when construction is completed. When starting an infrared inspection program, decide what you want from your program. This is best done by asking yourself the following questions:
- What is the role of thermography – PPM, PdM, QA, or Condition Assessment?
- Which systems/equipment do I want to inspect?
- How will thermography improve operations – decrease unscheduled downtime, improve product quality, and reduce production losses?
- What data are available for measuring the program’s effectiveness?
Once these questions have been answered, one can begin to set up an infrared inspection program with necessary equipment, staff, and support personnel. By beginning with the end in mind, an infrared inspection program is more likely to succeed by providing value and producing measureable results.
Designing an effective infrared inspection program is one of the many topics covered in the Infraspection Institute Level III Certified Infrared Thermographer® training course. For more information including course locations and dates, visit Infraspection Institute online at www.infraspection.com or call us at 609-239-4788.
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Infrared Inspection of Breaker Control Cabinets
Tip provided by: Brady Infrared Inspections, Inc.
Infrared inspections of electrical systems often include high visibility equipment such as substations, switchgear and motor controllers. In this Tip we discuss several critical items that are often overlooked during infrared inspections.
Perhaps one of the most overlooked pieces of equipment during an infrared inspection of electrical substations and indoor electrical switchgear is the control cabinets located beneath breakers in outdoor substations and above or on the side of rack-in breaker bays on 480V and higher indoor switchgear.
Equipment inside these cabinets is comprised of both AC and DC current and includes relays, conductor terminal connections, current transformers, breakers, and fuses. The primary function of this equipment is to activate the trip mechanism of a breaker if voltage or current conditions fall outside the specified trip settings.
Connection failures and other heat related damage to equipment inside these cabinets can cause a breaker to trip resulting in widespread power outage throughout a community and/or a facility. Given the vital importance of this equipment, it should be on every thermographer’s inventory list to inspect.
Below are a few examples of thermal problems that can be detected in these cabinets:
1) Image 1 shows internal heating on a breaker,
2) image 2 shows heating of a impregnated ribbon bus on a relay circuit board, and
3) image 3 shows heating on a plug-in fuse responsible for the switchgear cabinet heater
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IR Inspections to Detect In-floor Heating System Leaks
Hydronic in-floor heating systems are well known for the comfort they provide. Under the proper conditions, thermal imaging can be used to help find leaks that develop in these systems.
Hydronic in-floor heating systems are one option for providing heat to occupied spaces in homes and buildings. A type of radiant heating, hydronic in-floor systems are constructed with rigid or flexible tubing that carries hot water or other fluids below the surface of floors. The heat flowing through the tubing is conducted to flooring materials which radiate heat to occupied spaces above the floor.
In framed construction, radiant tubing may be suspended underneath subfloor materials. It may also be installed above the subfloor by embedding it within engineered plywood panels that have grooves to hold the tubing. Another popular construction detail involves embedding the tubing within concrete slab flooring.
Over time, hydronic systems can develop leaks. For framed construction or installations where tubing is embedded in plywood, finding a leak can be fairly straightforward. For systems embedded within a concrete slab, pinpointing the source of a leak can be nearly impossible.
By using a thermal imager while the system is under load, it is possible to detect thermal anomalies created by leaks from radiant tubing embedded in a concrete slab. Such thermal anomalies appear as amorphous hot spots which tend to flare around the regular straight lines created by the pathway of tubing that is not actively leaking.
To help ensure accurate results, it is best to begin with the heating system off and the slab at or below ambient temperature. A load should then be applied to the system by adjusting the building’s thermostat to call for heat. As the system begins to heat the floor, a thermal imager is then used to inspect the top surface of the floor in an organized fashion.
Depending upon one’s circumstances, it may take up to a half hour or more for thermal patterns to emerge and become clear. It is recommended that imaging begin shortly after the radiant system is activated and continue until clear thermal imagery is seen for all subject areas. Best results will be obtained when flooring is not covered with thick materials such as carpet or wood planks.
During imaging one may see slightly warmer areas where tubing is spaced close to adjacent tubes or has not been buried as deeply as other tubing. Areas exhibiting thermal anomalies should be invasively tested to confirm the presence of leaks.
Thermal imaging of radiant in-floor heating systems is an application that is covered in all Infraspection Institute Level I training courses. For course locations and dates or information on our Distance Learning program, visit our website or call us at 609-239-4788.
Careful Testimony at Your Fingertips
Tip provided by: Robert J. Incollingo
Attorney at Law
856-857-1500
www.rjilaw.com
When called on to answer a question under oath, put your left hand on your lap, fingertips to your pant leg and think about the tip of your thumb. Your thumb reminds you that you have a predicate question of your own to answer for yourself, before you can even begin to reply to the other person. Counting on your thumb reminds you to ask yourself first, “Did I hear the whole question?” There are lots of reasons why you might not hear a question; your mind wanders, someone in the room speaks or coughs on top of the question, you don’t hear so well, outside traffic noise spikes, a distractingly pretty girl wanders past, or the inquirer mumbles in a heavy accent while covering his mouth with his hand. Maybe you were thinking of your thumb. If you didn’t hear the whole question, you cannot answer but to reply, “I didn’t hear the question. Could you please repeat it?”
If you did hear the question, your index finger should twitch. Your index finger is trying to remind you to ask yourself, “Did I understand the question?” There are lots of reasons why you might not understand a question; you don’t know a word, a word you know is being used in an unknown context, the question assumes a fact which is not true or not in evidence (of the “when did you stop beating your wife” variety), or the question is a leading question that incorporates a statement which it asks you to admit or deny, and as phrased you can do neither (such as, “You were wearing pants this morning when you hit my client, weren’t you?”). Sometimes, the question isn’t even a question, but a form of copspeak, a statement coupled with a pregnant pause. (Here your lawyer should jump in and state loudly for your benefit, “Objection as to form. No question pending.”) We must also admit the possibility that you are a dullard, the question is beyond you, and this whole business of questions reminds you unpleasantly of school.
If you didn’t truly understand the whole question, you must sensibly ask the questioner, “I didn’t understand the question. Could you please rephrase it?” Be prepared to get another question in return, “What part didn’t you understand?” Look blank for a meaningful second, and reply, “I’m not sure. If you rephrase it maybe I can answer.”
If you heard and understood the question, your middle fingertip will press against your leg, insistent that you ask yourself, “Do I know the answer? If not, is it because I don’t know the answer, or because I forget the answer?” This distinction makes much more of a difference on the stand than in regular life. If you knew something but forgot it, your recollection can be refreshed and introduced into evidence. If you never knew it, your testimony is not competent on this point, and is thus worthless forever. Sorry.
Should you reply, “I don’t know,” expect the follow-up question, “Well, who would know?” Look blank, and start on your thumb again. If you know who would know, say so and stop talking. Otherwise, feel free to say you don’t know who would know. They can’t mess with you this way.
Should you reply, “I don’t remember,” expect the follow up question, “Can you think of any documents which would tend to refresh your recollection?” Look blank, and start on your thumb again. And so on.
If you know the answer, your ring finger will tap and twitch to tell you that you are in the greatest danger of all. The pressure of your ring fingertip against your leg reminds you that you must answer the question truthfully in a manner that is only apparently helpful, and then stop talking. Answer only the question asked, which you are now presumed to have heard and understood, and coming to the very first period at the end of the very first sentence of your answer, stop talking. Stop talking. STOP TALKING. Do not answer the question you believe should have been asked; do not tell the questioner what you think she needs to know; do not answer a question with a question; do not object, or protest to your lawyer or the judge, “Do I have to answer that?”; do not preface your answer with an aside such as, “Can we go off the record for a minute here?” Instead, respond only to the question asked, as briefly and as generally as you can get away with, without obstructing justice. Do not blather, do not be helpful to the questioner, do not be funny, do not let your temper run away with you, do not lie. Answer in as few words as possible and then, you guessed it, stop talking.
And your little finger? Well, your little finger goes, “wee, wee, wee” all the way home. We thought you knew that.
Robert J. Incollingo, Esquire
1010 Kings Highway South – Building One Floor 1
Cherry Hill, NJ 08034
856-857-1500
www.rjilaw.com
Bob Incollingo is an attorney in private practice in New Jersey and a regular speaker at Infraspection Institute’s annual IR/INFO Conference.
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Using an Auto Image Function
Auto Image is a feature found on many modern thermal imagers. While this feature may be helpful in certain imaging situations, its usage can cause thermographers to overlook significant thermal anomalies.
Humans have come to rely on technology to make our lives easier. We frequently take for granted how many mundane chores of the past have been automated. Each day we rely upon automatic transmissions in our cars, auto correction in word processors, and auto flush in lavatories. As infrared imaging has matured, automatic image adjustment has become a common feature on thermal imagers.
Auto Image, also known as auto adjust, is a feature commonly found on today’s thermal imagers. When engaged, the thermal imager will automatically adjust Level and Gain values so that the coldest and hottest objects within the imaged scene will be set as the lowest and highest temperature limits respectively. Auto Image may be for a single frame or it may allow for constant adjustments to automatically take place in real time.
While single-frame auto image may provide a good starting point for level and gain settings, full time usage of auto image will cause level and gain values to constantly change as the imager is panned across a given target. With values constantly changing, it is nearly impossible to make comparisons between imaged objects since there is no fixed, baseline value. In addition to making thermal imaging confusing, the use of fulltime auto image will cause many thermal anomalies to go undetected.
Thermographers who own thermal imaging equipment should familiarize themselves with their equipment to determine if their imager features automatic image mode(s). For imagers featuring single frame auto, a thermographer may use this feature to allow the imager to ‘suggest’ initial level and gain settings. For scenes that do not have a wide variation in temperature such as building envelopes or roofs, auto image may provide optimal imagery. If not, the thermographer should then manually adjust the imager’s level and gain settings in order to optimize the displayed image.
For thermal imagers that do not have onboard level and gain controls or for those that feature full-time auto image, the technique for optimizing the displayed image is as follows:
- Set imager to Auto Image mode
- Aim and focus imager on item of interest
- Pan imager slightly to obtain optimal contrast within scene
- Immediately switch to Manual mode to lock range/level settings
- If possible, adjust range and level controls to further optimize displayed image
With the above steps completed, the thermographer may continue imaging similar objects under similar conditions. Should scene conditions change, the above steps may be repeated as necessary.
Properly adjusting level and gain is an extremely important part of thermal imaging. For best results, a thermographer should never rely on full time auto image to provide optimal imagery.
Thermal imaging selection and operation are two of the many topics covered in all Infraspection Institute Level I training courses. For course locations and dates or information on our Distance Learning program, visit our website or call us at 609-239-4788.
Using Switchgear Windows and Ports
Tip written by: Infraspection Institute
As the popularity of switchgear windows and ports grows, thermographers are faced with challenges unique to these devices. In this Tip we examine some of these challenges and provide advice and cautions when imaging through windows and ports.
In an effort to reduce the risk of injuries associated with arc flash, many facilities have installed IR transmissive windows or ports that permit infrared inspections without having to open panel covers. Although windows and ports can provide a measure of safety and help to reduce labor associated with infrared inspections, they pose unique challenges not associated with direct line-of-sight imaging.
Switchgear windows are typically constructed of a metal frame with a fixed IR transparent material that enables an imager to view through them. Switchgear ports consist of a metal frame with small openings through which an imager may be sighted. Depending upon type, some ports have a single hole; others have metal screens containing multiple holes.
Windows and ports will always attenuate infrared energy received by the imager. This attenuation will affect both qualitative and quantitative data; however, the greatest challenge posed by windows and ports involves temperature measurement. Due to their small opening it is not possible to accurately measure temperature through screened ports. Accurate temperature through windows and single opening ports is possible only if the following conditions are met:
- Window opening must be larger than IR lens objective
- Target must be at or beyond imager’s minimum focus distance
- Both window transmittance and target emittance values must be known and properly entered into imager’s computer
- Imager lens must be kept perpendicular to, and in contact with window
When it is not possible to meet all of the above conditions, imagery should be evaluated only for its qualitative value. As always, any inexplicable hot or cold exceptions should be investigated for cause and appropriate corrective action taken.
The Infraspection Institute Standard for Measuring and Compensating for Transmittance of an Attenuating Medium Using Infrared Imaging Radiometers provides procedures for calculating window transmittance which is critical to accurate temperature measurement. To obtain a current copy of the Standard, call 609-239-4788 or visit the Standards area of our online store.
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Connecting the Dots
One of the most challenging aspects of performing infrared inspections involves directing a qualified assistant in outlining exceptions on the surface of the ground or an insulated roof.
Thermographers who perform infrared inspections of flat roofs or underground piping systems often outline the perimeter of exceptions with spray paint. Directing a qualified assistant to accurately outline exceptions can be both time-consuming and frustrating. The following suggestions can help to speed inspections while preserving coworker relations.
- When using spray paint to mark at ground level, use a spray paint and dispenser designed for the task
- Make sure surfaces to be marked are clean and dry and will not be damaged by spray paint
- Never spray paint where wind may carry paint to unintended surfaces
- Be certain of target before marking – make certain shoes/hands are clear
- Consult Material Safety Data Sheets before using spray paint for any health and usage precautions
When outlining the perimeter of an exception, use a series of dots to outline the most prominent features of the exception. These dots can then be connected with a solid line once their location is deemed satisfactory. Depending upon weather and target conditions, spray painted lines will often show clearly within the thermal image.
Infrared inspection of flat roofs is one of the many topics covered in all Infraspection Institute Level I training courses. For more information on thermographer training or to obtain a copy of the Standard for Infrared Inspections of Insulated Roofs, visit Infraspection.com or call us at 609-239-4788.
Using an IR Imager to Monitor Drywall Installation
Finishing drywall is a routine part of commercial and residential construction. A thermal imager can be useful in helping to assess the drying process associated with newly-installed compound.
Drywall compound is a white powder consisting of gypsum dust mixed with water to form a mud with a consistency similar to cake frosting. Drywall compound is used with paper or fiber joint tape to seal joints between individual sheets of drywall and to cover fasteners in order to create a seamless finish on interior walls.
Drywall finishing often requires multiple coats of compound which are applied over several days to provide the desired surface quality. For best results, previously applied layers of compound should be thoroughly dry before successive coats are applied. Water evaporating from freshly applied compound causes pronounced cooling which can be readily detected with a thermal imager.
When using a thermal imager to inspect drywall compound, keep the following in mind:
- Choose an imager with sufficient thermal sensitivity and resolution
- Ensure that humidity and temperature levels are conducive to drying
- Always manually adjust imager’s level and gain controls for best thermal contrast
Lastly, missing or damaged insulation may create thermal anomalies across inspected walls; however, such thermal patterns will often be much larger than compounded areas.
Thermal imaging of buildings is one of the many topics covered in all Infraspection Institute Level I training courses. For course locations and dates, or to learn more about our Distance Learning program, call us at 609-239-4788 or visit online at Infraspection.com
How to Calculate Transmittance
Tip written by: Infraspection Institute
Windows are semi-transparent materials placed between an object and an infrared instrument to separate conditioned from unconditioned spaces. When measuring temperatures through a window, it is imperative to know and enter the Transmittance value of the window into your radiometer’s computer to help ensure temperature measurement accuracy.
Because no object is 100% transmissive, infrared windows will always have Transmittance values of less than 1.0. Following the procedure listed below, it is possible to calculate the T value of any window.
Equipment Required:
- Calibrated imaging radiometer with a computer that allows user to input Reflected Temperature and Emittance values.
- Blackbody simulator with E ≥ 0.95 heated close to temperature of target to be measured.
- Window that is semitransparent in the waveband of the imaging radiometer.
Method:
- Place imaging radiometer at desired distance from blackbody simulator.
- Aim and focus imager on blackbody simulator. Place crosshair on center of blackbody simulator.
- Set imager’s E control to 1.0
- Measure and compensate for Reflected Temperature.
- Measure and note apparent temperature of blackbody simulator.
- Place window directly in front of imaging radiometer’s lens.
- Without moving imager, adjust E control until observed temperature matches value obtained in Step 5 above. The displayed E value is the Transmittance percentage for this window with the subject imaging radiometer. For greater accuracy, repeat above steps a minimum of three times and average results.
The above procedure is described in detail in the Standard for Measuring and Compensating for Transmittance of an Attenuating Medium Using Infrared Imaging Radiometers available from Infraspection Institute. For more information or to place an order, call 609-239-4788 or visit the Infraspection Online Store.
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Negative Findings Versus No Problems
Tip written by: Infraspection Institute
When documenting an infrared inspection with no detectable exceptions, thermographers should be aware that there is a big difference between reporting “no problems” versus “negative findings”.
Infrared inspections may be performed for a wide variety of reasons including condition assessment, quality assurance and predictive maintenance. In its simplest form, thermography detects, displays and records thermal images and temperatures across the surface of an object. In many cases, thermal anomalies are indicative of deficiencies, changes, or undesirable conditions within the object or system being inspected. Typically, such conditions are reported with a thermal image and a description of the anomaly.
Upon completing infrared inspections during which no anomalies are detected, thermographers will frequently report that the subject system has “no problems”. From a liability standpoint, this can increase a thermographer’s risk since there may exist problems that are simply not detectable by thermography. Most importantly, a proclamation of “no problems” may leave an end user with a false sense of security regarding the condition or integrity of the subject system.
Since it is not possible for thermography to detect all potential problems within a given system or object, it is advisable for a thermographer to report “negative findings” when no anomalies are detected. This statement is direct, to the point, and in accordance with terminology utilized in other types of scientific testing.
Although the difference between “no problems” and “negative findings” may seem small, the proper use of terminology can help to prevent costly and embarrassing misunderstandings.
Generating standards-compliant reports is one of the many topics covered in all Infraspection Institute Level I training courses. For more information on thermographer training, visit Infraspection.com or call us at 609-239-4788.
What Do Thermometers Measure?
Tip written by: Infraspection Institute
When asked what a thermometer measures, most people will tell you that thermometers measure whatever they contact. The correct answer is a little more complex and is fundamental to understanding and accurately applying contact thermometry.
Contact thermometry is a common technique used in temperature measurement. Thermocouples, resistance temperature devices, thermistors, and bulb thermometers are used to gauge the temperature of a wide variety of objects, materials, and systems. Although each works on a different principle, all contact temperature devices have one thing in common: contact thermometers report their own temperature.
Because contact thermometry is often used by thermographers to confirm radiometric measurements and to calibrate infrared equipment, accuracy is extremely important. To help ensure accuracy when using a contact thermometer, keep the following in mind:
- Select thermometer appropriate for task. Be sure to consider sensor size, thermometer sensitivity, operating range, and response time
- Prior to use, confirm that chosen thermometer is calibrated and operating properly
- Make certain that selected thermometer is in good contact with object
- Allow sufficient time for thermometer to achieve thermal equilibrium with object
Prior to using a contact thermometer, make certain that the surface to be measured is safe to touch. Never use a contact thermometer on energized electrical equipment or on any machinery where contact could result in personal injury.
Advanced heat transfer and temperature measurement are some of the many topics covered in the Infraspection Institute Level II Certified Infrared Thermographer® training course. For course schedules or to register for a course, visit Infraspection Institute online or call us at 609-239-4788.
Infrared Imaging and Mold Detection
Tip written by: Infraspection Institute
As concerns regarding indoor air quality increase, there is increasing concern with respect to mold. Used properly, a thermal imager can help identify areas of potential mold growth.
Mold is a ubiquitous single cell organism that tends to favor moist environments. Of the thousand species of mold found worldwide, many are harmless; however, certain species are toxic. Others can cause chronic health problems in humans.
While thermal imagers cannot detect mold directly, they can often detect evidence of the latent moisture often associated with mold presence. When using a thermal imager to detect latent moisture, keep the following in mind:
- Evidence of moisture can only be detected if a temperature differential exists across the surface of the material being inspected.
- Frequently, a delta T can be created by actively heating or cooling a structure or by relying on solar loading of the subject areas.
- Subject building components should be imaged from both indoor and outdoor aspects under the correct weather conditions.
- Suspected moisture presence must be confirmed by independent means.
- A negative finding for latent moisture does not guarantee that mold is not present.
Since moisture presence is not positive proof of mold presence, further laboratory tests will be required to confirm mold within any moist areas detected.
Using thermal imaging to detect latent moisture within buildings is one of the many topics covered in all Infraspection Institute Level I training courses. For more information on thermographer training or to obtain a copy of the Standard for Infrared Inspection of Building Envelopes, visit Infraspection Institute or call us at 609-239-4788.
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Tornado Safety
Tip written by: Infraspection Institute
With the onset of warm weather, tornado season has arrived. In an average year, tornadoes in the US cause 80 fatalities and 1500 injuries. Knowing what to do before and during a tornado is crucial for survival.
Tornadoes are nature’s most violent storms. Spawned from powerful thunderstorms, tornadoes can cause fatalities and devastate a neighborhood in seconds. A tornado appears as a rotating, funnel-shaped cloud that extends from a thunderstorm to the ground with whirling winds that can reach 300 miles per hour. Damage paths can be in excess of one mile wide and 50 miles long. Every state is at some risk from this hazard.
Some tornadoes are clearly visible, while rain or nearby low-hanging clouds obscure others. Occasionally, tornadoes develop so rapidly that little, if any, advance warning is possible. The best defense against tornadoes is to be alert to weather conditions and be ready to seek shelter.
Before a tornado, be alert to changing weather conditions.
- Listen to NOAA Weather Radio or to local newscasts for the latest information
- Watch for approaching storms
- Know the danger signs: Dark, often greenish sky; large hail; large, dark, low-lying or rotating clouds; loud roar, similar to a freight train
If you see an approaching tornado or are under a tornado WARNING, seek shelter immediately.
- If you are in a structure, go to a pre-designated shelter area or the center of an interior room on the lowest building level. Get under a sturdy table and use your arms to protect your head and neck. Do not open windows.
- If you are in a vehicle, get out immediately and go to the lowest floor of a sturdy, nearby building or a storm shelter. Mobile homes, even if tied down, offer little protection from tornadoes.
- If you are outside with no shelter, lie flat in a nearby ditch or depression and cover your head with your hands. Beware of flying debris and the potential for flooding.
For more information on tornadoes and tornado safety, visit the NOAA website.
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Infrared Inspections to Detect Process Piping Corrosion
Tip written by: Infraspection Institute
Infrared thermography offers good potential for detecting energy losses from process equipment and piping as well as some symptoms of pipe deterioration.
It is important to remember that thermography is a line-of-sight technology that detects thermal patterns and associated temperatures across the surface of an object.
Subsurface characteristics or defects cannot be detected by thermography unless they cause a temperature differential of at least 0.1 Celsius degrees across the surface of the object being inspected. Presently, interior corrosion detection is best detected with ultrasonic thickness testing; exterior corrosion may be detected by visual examination.
Thermography may prove useful if corrosion is being caused by water saturated insulation surrounding your process piping. If this is the case, water saturated insulation should show excess energy loss at the point where the water is entrapped. It will be necessary to visually inspect the pipe to confirm the actual condition of the pipe.
When performing thermal imaging, be aware that weather conditions such as solar gain, wind and atmospheric attenuation can adversely affect your results. Be certain that your imaging system is capable of detecting the anticipated defect by understanding how emissivity, spectral response and spot size will affect your inspection.
Infrared inspections of process equipment is one of the many topics covered in the Level I Infraspection Institute Certified Infrared Thermographer® training course. For information on thermographer training including course locations and dates, visit us online at www.infraspection.com or call us at 609-239-4788.
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The Value of Level III Certification
Tip written by: Infraspection Institute
Certification is one of the most frequently cited credentials for practicing infrared thermographers. In this Tip we discuss the importance of Level III certification and why thermographers need to train and certify to the highest level possible.
The advent of lower priced equipment has created greater public awareness and a dramatic increase in infrared imager sales. Sales of imagers to contractors, service companies, engineers and consultants are at an all-time high. As a result, many areas have seen an increase in competition among those who provide professional infrared inspection services.
In addition to an increase in the number of firms providing infrared inspection services, many infrared consultants are often competing with poorly trained thermographers with little or no field experience. The following practices can help customers and prospects appreciate the true value of an experienced consultant and to level the playing field in competitive situations.
- Obtain quality training for all thermographers. Training should be from a recognized, independent training firm
- Implement a meaningful written practice for your thermography program. This simple step serves as a blueprint for an infrared inspection program and helps to ensure quality
- Emphasize thermographer field experience in addition to training. Clients often place value above low price and will spend more money for your services if they believe that you are better qualified than a lower priced competitor
Lastly, train and certify all thermographers to Level III. Training to minimal levels sends a poor message to clients and limits a thermographer’s knowledge base and revenue potential. Requiring Level III for all thermographers can provide a competitive advantage and increased profits.
Infraspection Institute has been training and certifying professional infrared thermographers since 1980. Our Level III Certified Infrared Thermographer® training course teaches the industry’s best practices and is fully compliant with ASNT and industry standards. Our highly experienced instructors provide up-to-date information vital to help maximize your program’s success and profits. For more information or to register for a class, call 609-239-4788 or visit us online at www.infraspection.com.
Insect Safety Tip
Tip written by: Infraspection Institute
For many, it’s that time of year again when nature’s little wonders come out and remind us that we need to be proactive in reducing our exposure to the flying and crawling types of hazards. In this Tip, we offer suggestions for dealing with mosquitoes, ticks, and bees.
Mosquitoes – Nationwide there are more than 60 different kinds of mosquitoes some of which are capable of spreading disease. Mosquito larvae can develop in both tidal and fresh water locations; the key to minimizing their population is to reduce the availability of standing/stagnant water. Treat, remove or drain “water collectors” such as cans, discarded tires, etc. A single discarded tire can produce tens of thousands of mosquitoes over the course of a season! An insect repellant can help protect you from bites.
Ticks – Ticks like to rest on low-lying brush and “catch a ride” on a passersby. Areas prone to tick infestation are wooded areas and low-growing grasslands. The best way to reduce your risk of tick-bites is to avoid infested areas. When venturing into tick prone areas, stay in the center of paths, avoid sitting on the ground, and conduct frequent tick-checks. Dress properly by wearing a long-sleeved shirt and long pants, tucking your shirt into your pants and your pants into your socks. This reduces the skin area exposed to ticks and thwarts their efforts to crawl onto your skin. Again, an insect repellant can help protect you.
Bees – Keep a lookout for nests and the activity associated with them especially when opening cabinets or enclosures where bees might nest. For small nests or individual bees, knock down sprays may be effective. For large nests or colonies, contact a professional to have them removed.
Medical Attention – Be alert for signs of an allergic reaction to insect bites or stings. Non-emergency symptoms vary according to the type of insect and the individual. Most people have localized pain, redness, swelling, or itching. Signs of severe reaction which require immediate medical attention include trouble breathing, wheezing, shortness of breath, weakness, swelling anywhere on the face and a tightening throat. In such cases, seek medical treatment immediately!
Thermographer safety is one of the many topics covered in the Infraspection Institute Level I Certified Infrared Thermographer® training course. For more information on open enrollment classes or our Distance Learning courses, visit Infraspection Institute online at www.infraspection.com or call us at 609-239-4788.
